1. Field of the Invention
The present invention generally relates to lubrication systems for motors and more particularly relates to lubrication systems used with outboard motors.
2. Description of the Related Art
Outboard motors often have a lubrication system for providing a lubricant to an internal combustion engine. Japanese Patent Publication No. Hei 5-278687 discloses an outboard motor equipped with a lubrication system. The outboard motor includes a vertically extending case pivotally supported on a hull of a boat. The lower portion of the outboard motor can be submerged in water in which the boat floats. A rotatable propeller is supported by a lower end portion of the case. The outboard motor has an internal combustion engine supported within the upper end portion of the case. The engine drives the propeller to propel the boat.
The outboard motor has an oil pan for holding lubricant oil that is used by the internal combustion engine. An oil pipe has a lower end opening into the deepest portion of the inside bottom of the oil pan and an upper end extending towards the internal combustion engine. An oil pump operates to draw oil from the oil pan through the oil pipe towards the internal combustion engine.
When the internal combustion engine operates, the propeller is driven by the engine to propel the boat. The engine also drives an oil pump so that lubricant oil in the oil pan is fed through the oil pipe to lubricate various components of the engine.
In the lubrication system, an inside surface of the oil pan is sloped down towards the rear of the outboard motor. To discharge the lubricant oil in the oil pan (e.g., to change the lubricant oil), the lower part of the outboard motor is swung up. Once the outboard motor is rotated upwardly, the inside front surface of the oil pan is sloped downwardly towards the boat so that the lubricant oil in the oil pan is discharged to an oil receiver.
Unfortunately, the lubrication system has a complicated design. Additionally, the inside front surface of the oil pan is sloped down rearwardly when the outboard motor is positioned within the water. As such, the oil pipe and the oil pump are spaced widely apart from each other in the longitudinal direction of the boat. As such, the oil passage between the oil pipe and the oil pump may be overly complicated.